Hypodermic syringe



May 7, 1929 E. P. CRESSLER HYPODERMIC SYRINGE Original Filed Jan. 30, 1924 Patented May 7, 1929.

UNITED STATES FUPATENT OFFICE.

EDWARD IP. CRESSLER, OF NEWTON, KANSAS, ASSIGNOR TO COOK LABORATORIES, INC., OF CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE.

HYPODERMIC SYRINGE.

original application filed January 30, 1924, Serial No. 689,518. Divided and this application filed March This application is a division of my lapplication filed January 30, 1924, Serial I 0. 689,518, relating to hypodermic syringes of the cartridge type.

In said prior application, I disclose several examples of a syringe organizat on embodying a cartridge or sealed container f hypodermic fluid, contractible in interior volume for expelling the contents, and the discharge end of which is controlled by internal fluid pressure for establishing communication with a hypodermic injecting needle when the pressure is applied and for shutting off communication with-the needle yvhen the pressure is released, so as to avoid the drawin of blood or foreign matterlfrom the patient s tissue into the injecting needle by any suction eifect in the cartridge accompanying rebound or retractive movement of the syringe plunger. More specifically, the cartridge is sealed at its discharge end by a flexible closure so constructed as to provide a central passage therethrough which is opened by outward flexing of the closure under pressure imposed on the liquid in the cartridge and closed by reflexing of the sealing closure when the pressure on the liquid is released. The injecting needle of the syringe organization has or is connected with an inner funnel extension the inner larger end of which bears against the outer face of the cartridge sealing closure, thus providing anannular seat or abutment cooperating with the flexible closure to control its flexing movement and to assure discharge of the Serial No. 263,670.

ter, are respectively shown in the drawings hereunto annexed.

i In said drawings:

Fig. l is a longitudinal section of said syringe or injection-administering organization;

Fig. 2 is a longitudinal section of the cartridge;

Figs. 3.. and 4 are enlarged sections of the discharge end of the cartridge, the section of Fig. 4 being taken at right angles to the section of Fig. 3.

As represented in the drawings, a plug 2 of resilient material such as soft rubber or the like, fitted as a stopper in the fore end of the glass cartridge tube 1, and formed with a flange overlying the edge of the glass tube, seals the discharge end of the illustrative cartridge. Said plug has at its center a conical cavity 2 extending through the plug from its inner side, and a slit or incision 2 cut in the outer side of the plug and meeting the cavity 2*. The form and relation of said cavity and slip are such as to provide in efiect a pressure-controlled valve opening outwardly under pressure imposed on the liquid in the cartridge, to permit'discharge of the liquid,'and automatically closing when the pressure is released. That is to say, normally or in the absence of pressure on the contained fluid the walls of the slit 2 are pressed tightly together, but when pressure is imposed on the liquid by forcing in the rear piston plug 3 the plug or its central portion will flex, so that the walls of the conical cavity 2 will tend to become parallel to each other and the walls of the slit 2 will separate from each" other, thereby opening a passage. in the sealin plug, and when the pressure is released the reflexing of the plug will press the walls of the slit together and close said passage.

In the syringe organization, the hypodermic needle 4 has an inner funnel extension 5, preferably integral with the needle. The needle funnel 5 is held with its inner edge against the outer face of the sealing. plug 2, surrounding the central passage thereof, thereby presenting an annular ledge or seat cooperating with the sealing plug to control its flexing and to assure the dispart way charge of the liquid ejected from the cartridge into and through the needle via the funnel. v

The cartridge is shown fitted in a tubular syringe body or cartridge holder 6, having longitudinal sight openings 7. A head 8 screwed on the fore end of the syringe body provides an abutment for the sealing plug 2. This head 8 has an exteriorly threaded tubular nipple 9 of sufficient internal diameter to accommodate the needle funnel 5. The needle holder 10 comprises a screw cap screwed upon the nipple 9, said cap having a tapered axial bore to fit the needle funnel 5,. so that the needle is held substantially rigidly with the inner end of the funnel bearing against the outer face of the sealing plug 2.

The cartridge plug 3, functioning as a piston to be forced inwardly to cause the opening of the passage in the discharge end of the cartridge and ejection of the fluid, is represented as a composite plug comprising a relatively thicker hard rubber section 3" and thin soft rubber section 3*, the thicker section being fitted in the glass cartridge tube less snugly than the soft rubber section. When this composite plug is forced inward, the thicker harder section 2 will slide freely, and the soft section will trail behind it without marked binding tendency; but if the movement isreversed the softer rubber section traveling in advance of the harder rubber section will be expanded and spread so that its frictional contact with the interior of the glass tube will retardthe movement and act with a braking effect. This is advantageous in resisting tendency of rebound at theend of'the fluid-ejecting stroke of the syringe plunger.

The syringe plunger is shown as a rod 11 having a threaded end for screw engagement with the composite plug, the sections of which are formed with holes for such engagement, though it will be understood that the,plunger may be engaged with the plug otherwise. For operating the syringe, the operator grasps the finger pieces 12 attached to the rear end of the syringe body and bears with the palm of his hands on the handle 13 of the plunger rod to drive in the piston plug. The plunger rod is carried by the cap 14 detachably secured on the rear end of the syringe body, as for instance by means of pins 15 engaging bayonet slots in the rear end of the syringe body. A stop 16 on the plunger rod limits the outward movement of the rod. The proportions of the cartridge and instrument parts are desirably such that when the breech cap 14 is applied it will bear against the butt end of the cartridge tube and hold the cartridge substantially against longitudinal movement with the fore sealing plug 2 against the abutment provided by, the head 8. The

cartridge being so held and the flange of the plug 2 overlying the fore end of the glass tube, the needle may be held with the inner end of its funnel head seated against the sealing plug with desired pressure. In the fluid-ejecting operation, the end thrust imposed upon the glass cartridge tube is cushioned by the flange of the sealing plug, which is clamped between the head 8 and the glass tube, serving as a gasket and cushioning means and to protect the end of the tube.

It will be understood that in addition to the subject-matter herein claimed the illustrative cartridge and injection-administering organization embody broader subjectmatter claimed in my said prior application Ser. No. 689,518.

I claim herein:

1. A hypodermic syringe embodying a cartridge and needle in operative relation, said cartridge comprising a tube having liquid-confining plugs, one to be forced inward as a piston and the other constructed to provide a normally closed sealing stopper responsive to pressure imposed on the liquid to establish a discharge passage through the plug, said needle having a funnel held with its mouth against said plug and surrounding the passage therethrough,

with associated means holding the cartridge and needle in assembly and means for forcing in. said piston plug.

2. A hypodermic syringe embodying a cartridge and needle in operative'relation, said cartridge comprising a tube having liquid-confining plugs, one to be forced inward as a piston and the other sealing the discharge end of the tube and constructed to provide a pressure-controlled passage opened by pressure imposed on the liquid by the forcing in of said piston plug and closing when said pressure is released, with associated means holding the cartridge and needle in assembly and means for forcingin said piston plug.

35A hypodermic syringe embodying a cartridge and needle in operative relation, said cartridge comprising a liquid-containing tube having a rear piston plug and a fore sealing plug of elastic material having a flange overlying the end of said tube, said sealing plug constructed to provide a pressure-controlled passage opened by pressure imposed on the liquid by the forcing in of said piston plug and closing when said pressure is released, with a cartridge holder providing an abutment for said flanged sealing plug and having the needle removably connected therewith, and means for driving in the piston plug.

4. In a syringe organization of the character described, the combination with a liquid-containing cartridge contractible in interior volume. and having a sealing plug of elastic material constructed to provide a pressure-controlled passage openable by pressure imposed on the liquid, of a hypodermic injecting needle having an integral funnel held with its mouth against said plug around said opening, and associated means holding said cartridge and needle in operative relation.

5. A cartridge-holding body having a head to provide an abutment for the fore end of the cartridge inserted therein, said head having an externally threaded nipple of substantially large internal diameter to accommodate a needle funnel, and a needle-holding screw cap engaging said nipple having a tapered bore to fit the funnel and thereby hold the same with its mouth against the cart-ridge.

6. A syringe cartridge comprising a liquid-containing tube having liquid-confining plugs, one to be forced inward as a pis ton and the other having a pressure-controlled discharge passage adapted to open under pressure imposed on the liquid and to close when the pressure is released.

7. A syringe cartridge comprising a liquid-containing tube having liquid-confining plugs, one to be forced inward as a piston and the other comprising an elastic stopper having a flange overlying the end of the tube and constructed to provide a pressure controlled passage operable by pressure imposed on the liquid by the forcing in of said piston plug and adapted to close when the pressure is released.

8. A medicament container having a flexible rubber plug sealing one end thereof; said plug provided with a substantially axial cavity extending part way through the plug from the inner wall, and provided with an axial slit extending from the cavity to the outer wall of the plug; the plug being so constructed and arranged that the cavity is normally open, While the slit is normally closed, but under the pressure created during an injection, the body of the plug flexes and the slit is opened to permit discharge of the medicament through the passageway provided by the cavity and slit together.

9. A medicament container having a flexible rubber plug closing one end thereof; said plug provided with a substantially axial conical cavity extending part way through the plug from the inner wall, and also provided with a straight-Walled slit extending from the bottom or small end of the cavity to the outer wall of the plug; the plug being so constructed and arranged that the slit is normally closed to seal the container, but is opened by fiexure of the plug from pressure within the container.

In testimony whereof, I have signed my name to this specification.

EDWARD P. CRESSLER. 

